I've tried all four of them and they work fine but I only kept the battery one. It seems like whenever you install/uninstall one of these, the Sense UI needs to restart itself. I thought it crashed my phone at first but I think it probably has something to do with the new widgets integrating into the HTC widget list.

the battery one is the only one worth getting
dice is just dumb
this day in history is kinda neat, but i doubt i will use it, and i don't like the space it takes up
tip calculator? you mean you haven't figured out how to do this in your head yet?

I have a shortcut to SPare PArts on my home screen, and it has a link to the elusive battery info screen accessible only (as far as I can tell) through the nearly unuseable (for me, anyway) voice dialer.

If I use SPare Parts to bring that up, then use the home button to exit, tapping the SPare PARts shortcut opens the battery info screen.

For those who've never seen it, it gives battery scale, status, health, temp... and a few other things.